Brake operating mechanism



Jan. 15, 1935. F- H' BARTZ 1,987,728

BRAKE OPERATING MECHANI SM Filed Feb. 15, 1932 Q/ZM Inventor Attorney Patented Jan. 15, 1 935 l UNITED STATES PATENTQOFFICE a 1,987,728 Ii I? BRAKE OPERATING MECHANISM p Fred H. Bartz, Valparaiso, Ind. 7 Application February '15, 1932, Serial No. 592,871

' 4 Claims. (01. 188-10) My. invention relates to improvements in toa cam (not'shown) which actuates the brake brake operating mechanism, and it more esband as the leverrl ismoved by the foot pedal.

pecially consists of the features pointed out in It isa well knownmechanical feature in the the claims. use of levers that the most effective form of op- --5 The purpose of my invention is to simplify the erationis in the center. of its movement; that is, 5 adjustment of brakes in making compensation if the lever movement starts a considerable bit for the wearyof brake bands; :that eliminates the away from this point, each change of movement variable factor of ordinary lever movements as toward it gradually increases its effectiveness, applied to the operation of brake hands by the while on the other-hand as it graduallyrmoves substitution of segments or segment wheels; that away from this point in thesame direction the 10 alsoeliminates the usual adjustment of levers as effectiveness of. the movement is decreased, and the brake bands wear which adjustment must be it is to overcome this variable action that I have made separately for each wheel that is subdevised a system of segment control instead of a ject to braking action; that is applicable to two lever sothat the action throughout the system or four wheels; and that overcomes the variable will always be underthe same degree ofpull re- 15 braking effect usually present when levers are gardless'of Wh h m nt tands in reladepended upon. tion to the actuated cam which operates upon With these and other ends in view I illustrate the adjacent ends of the brake band. inrthe accompanying drawing such instan es of The defect of thelever system is illustrated in adaptation as will disclose the broad underlying 1 Where the l "o ov e t o the 20 features of the invention without limiting myself ve t ft O he Zero s indicated by 2 to the specific details shown thereon andxdea representing different DOSitiQhS. The scribed herein. movement tothe right of the zero is also indi- Figure 1 is an enlarged diagrammatic View catedby 1,:2"and 3' for different positions of the showing an ordinary brake lever adjustment and lever. The dottedlines showing diff p si- 25 the lack of uniformity of lever movement under tiOhS f the d 5 di a Where there is a graddifferent conditions of brake band wear, ual reduction of effectiveness as the lever is Fig. 2 is an enlarged diagrammatic view showm v o a more the right of t Zero ing how a uniform braking action is secured by poi t.

so meansof a, segment regardless of the extent of In eliminatingthe variable actions of the lever wear of the brake bands. 1, I substitute a segment 9, Fig. 2, also pivoted at Fig. 3 is a diagrammatic view of the mechani- 2. It hasthe arc-of a'circle110 on which a cable cal connections from two pairs of brake sag-i 12 is secured at..11. It will be seen that the pull ments to a foot pedal. on the cable 12 will always transmit a uniform $6 In installing my device I may use wh t 1- effectiveness on shaft 2 regardless'of the angular 5 ternatives or equivalents of construction that the position of the Segment itself- That dexigencies of varying conditions may demand less of the ease of adjustment of the shaft 13 to without departing from the broad spirit of the equalize the pull at a-point removed from the invention. brake drums there is secured an effectiveness and In the drawing an ordinary brake lever is inuniformity of pull, which is absolutely dependable 40 dicated by the numeral 1. It is pivoted at 2 to and 1 does not have the; variable'effect that is any *kind of cam action (not shown) adapted to present when a'lever is'u'sed, similar to Figure 1.

draw the adjacent ends of external brake bands There is no variation in the effectiveness of toward each other and separate the ends of inthe pull of the cable 12 regardless of the extent ternal brake bands (not shown). The housing of wear of the brake band. It will be understood to enclose the brake drum and brake bands may that the pivot point 2 of the segment 9 is the be of any desired type. same as that of the cam which operates the brake The arm or lever 1 is a uat d by a link 5 c nbands, as in the case of Fig. 1. The cables 12 nected to the foot Pedal y desired form o reaching from the segments 9 are attached to 50 retracting spring 8 may be combined with the rod other segments or wheels 14 secured on a shaft 5, the pedal 7 or the lever 1 to release the to which the foot pedal is attached through a brake. As ordinarily constructed each brake link in which a turn-buckle 16 is placed for adlever cooperates with a cam arm 3 through an justment. These parts may be associated with adjusting screw 4. The cam arm is connected any desired type of equalizing means. As the 55 foot pedal normally moves through a given distance a stop 17 is used to limit its rearward movement.

It is pointed out that when the brake band wears sufiiciently so as to cause the lever 1, Fig. 1, to not become effective until the numeral 3 is reached just before the zero line is reached, then, to set the brake it will be necessary to probably go as far as the numeral 3 to the right of the zero line. This increase in lever angle shows at once that the last portion of the brake action on the foot pedal is much less effective than when the lever is working at or near the vicinity of.

the zero line.

Compensation for this variablecoi idition can only be made by the adjustment of four set screws (4) one for each wheel, of lever 1, in engagement with the cam arm 3. This requires the services of a skilled mechanic and he usually makesseveral attempts before the desired equalization is accomplished. These adjusting "means .are usually in a very inaccessibleplace, incontrast to the ease of accessibility of the shaft 13, Fig. 3. However, the important point is to have a uniformly .efiective brake action as against the variable effective action when a lever is used.

The adjustment of my device requires no skill as a few turns of a tin'n-bucklezl6 will restore the effectiveness of brake action.

It will be seen that in the use of my invention I am able to at all times have the same effective action on each brake regardless of the change or the amount of wear of the brake bands. However, adjustments that may be necessary can be made on the shaft 13 which can be positioned in an easily accessible place on the chassis of the car or truck. Y

My invention maybe applied withequal success to two or four wheel brakes. It is immaterial as to the exact way the invention is applied because there are many variations that may be followed according to the structure of. the chassis of a specific car or truck. It will be seenthat the outstanding features of my system is the elimination of the variable action of any kind of brake that uses a lever arm to operate the brake bands and the use of one adjustment-whichis easily made compared to four adjustments necessary with a lever system. If the brake bands have become worn to such an extent that when the lever 1 must be moved beyond the position 3 at the right of the zero line it is quite apparent that each additional amount that it must be moved in this direction will reduce the effectiveness of pull, so that, if continued, very shortly the braking action will be gradually reduced to the point where there will be practically no effect upon the brake within the drum 15. In this way there is created a hazard not alone to the driver of the car or truck or delivery wagon but also a liability that the vehicle itself may be damagedbecause in an emergency the brakes can not be used.

What I claim is:

1. In a device to compensate for the wear of brake bands on an automobile, a foot pedal for operating the brakes, a connection from the foot pedal to a single shaft having separate segments adapted to operate the brake bands, a pivoted segment at each brake having a periphery constituting the arc of a circle, and means for attaching the connection from the foot pedal to the arc of one of the segments on'said single shaft whereby regardless of the wear of the brake bands there will always be the same uniform effective action of the brake for a given movement of the foot pedal. v

2'. In brake operating mechanisms, a foot pedal, a segmentsuitably attached to a single shaft, such segment having a portion of its circumference comprising an arc of a circle to which and from which an attachment is made to the foot pedal, a pair of disks on the said shaft, a segment for the brake of each rear wheel, a segment for the brake of each front wheel, a separate connection from each rear wheel segment to one portion of the periphery of each disk on the shaft, a separate connection from each front wheel'segment to a point on the periphery of each disk on the shaft approximately opposite the point of attachment of the connections from the rear wheel segments on said disk, means adjacent the foot pedal to compensate for any wear to which the separate brakes may be subjected, and separate springs associated'with each segment to release the brakes in opposition to the movement of the foot pedal in setting the separate brakes.

3. In a device of the character described, a brake segment, a hub forming a pivotal point, an arcof a circle forming the periphery of the segment, a spring to pull the segment in one direction, a disk on. a single shaft, a connection from the periphery of the segment to the disk on the single shaft, a segment on the same shaft, a foot pedal, and means between the foot pedal and the shaft segment for adjusting the starting and ending of the movement of the brake segment to a. predetermined point.

4. An operating segment for actuating the brake bands of automobiles, comprising a segment for each wheel having apivotal point and a periphery shaped as an arc of a circle of a given radius from the pivotal point, a spring for each segment to release its brake, a single shaft, a pair of disks on the shaft; a foot pedal, a connection from the foot pedal to the segment on said shaft, and separate connections from the disks to the arc of each wheel segment to set the brakes. and means between the foot pedal and theshaft segment for adjusting the movement of the foot pedal to compensate for whatever wear there may occur on the different brake bands.

FRED H. BARTZ. 

